gears and the automatic

[Osiris]

I'm ready to buy a set but I'd like some advice....

I thought about 4.10's but I'm worried about mpg ( the car is driven daily and I might be relocating somewhere where the commute is longer ).

I also want to consider 3.73's.

My question is, of course, How big is the difference with these two in terms of:

performance
mpg
drivability

Thanks for all your help!!!!

 

[kooldawg6]

If you're worried about the increased commute I would stick with the stock gears. I'd say go with the 4.10's. The difference in mpg from 3.73 to the 4.10 will be slight. Depends on driving style for the most part...increase in rpm=decrease in mpg.

 

[retfr8flyr]

I have 3.73 gears in my auto and I am very happy with the choice. If you will be doing very much highway driving IMO 4.10 are too much gear. With the 3.73 you are doing about 2500 rpm at 75 mph, with the 4.10 you will be doing about 2850 at 75. This may not sound like much difference but next time you are on the highway take overdrive off and cruise at 2850 for a while and then compare it to 2500. I have my tune form Doug at Bamachips and he also recommends 3.73 for the auto. He tried 4.10 and said they didn’t work well with the autos internal gearing for first second and third. I only lost about 1 mpg going with the 3.73’s.

Earl

 

[8850]

I doubt mileage would be much different in city traffic between the two gears. On the highway the 4:10 is a bit much.

If you go with a loose converter, Precision Industries 4000 stall for example, you can keep the 3.31 gear and get more et gains than any gear. Your city driving will suffer some with mileage but on the highway it will be no different than it is now with the converter locked.

Expect about .3-.4 et gains with the gear, stock converter. And .6-.7 with the converter and stock gear. Almost double the gain with the converter.

 

[kooldawg6]

I have 3.73 gears in my auto and I am very happy with the choice... I have my tune form Doug at Bamachips and he also recommends 3.73 for the auto. He tried 4.10 and said they didn’t work well with the autos internal gearing for first second and third.

Earl

At last, some specific advice from a guy who gets his hands dirty with these cars. I have driven mine on the highway at speed with O/D off and is tolerable, but hearing the tranny gears just don't cooperate to well with the 4.10s...it may well change my mind about the 4.10's. Thanks retfr8flyr for the scoop from Doug.

 

[seattlegt]

I have 4.10's in my auto and love them. I drive 65-70mph and it's fine. Only lost about 1/2 mpg. Pick up is great.

 

[Osiris]

Ok, now for the next question, who has the best price on Ford Racing ( NOT Motive ) gears?

 

[Kiernan]

I had 4.10's in my '04 and now have 3.73's in my '06. The 4.10s certainly gave better acceleration but the highway RPMs were too high for my taste. Granted, it was in a 4 speed and not our new 5 speed, but it was still high enough to leave a bad taste in my mouth.

The 3.73's gave a decent gain in acceleration without the excessively high highway RPMs. I'm pleased with going 3.73's over the 4.10's.

Also, I've read numerous complaints of people not being able to get good launches with 4.10's in the '05+. I don't have first hand experience with comparing launches...just what I read.

I lost about 1 MPG in the city, but gained it back when I put my JLT intake in.

 

[Osiris]

Thanks Kiernan, noticed your local as well...Ever run it at SAR?

 

[mongoose101]

I have 4:10s and love the way it jumps when I gas it no matter what the speed but I also have tall tires that give me a final ratio of 3:85. If I do it over I will go to with 3:73 and shorter itres. I do drive with the OD off when not on the big road.

 

[Kiernan]

Thanks Kiernan, noticed your local as well...Ever run it at SAR?

No, I've never run it, though I'd like to. Not having a helmet has kept me away, honestly. Me and a few friends are planning a trip out there some Wednesday to just watch, though.

If you're going to get gears installed locally, let me know...I might be able to hook you up with the guy that did my install on the '04 and '06.

 

[Osiris]

Sweet.

I might take you up on that as I have a good price on the gears and am going to purchase today.

FWIW I ran at SAR both on T&T Wednesday and MM, both times running a sub 14 ( they say they require a helmet for 13.99 and under ) and no one ever said anything to me at all.

 

[wotfr]

Are the internals identical i.e. bearing kit for the 8.8 on S197? I ask because I have a 3.73 ring and pinion and bearing kit I bought for my fox but would rather install in my '06, with the extra weight it would need it and with the modular it would love it. Also do you have to remove the panhard bar to do the swap? Thanks in advance.